5 Important Things to Know About U.S. Catholics

PRINCETON, N.J. -- Pope Francis' first trip to the United States provides a good opportunity to review the state of Catholicism in the U.S. What follows are five important points about Catholics, based on Gallup data that in some cases go back as far as the 1940s.

Catholics Are 23% of U.S. Adult Population

Catholics constituted 23% of the U.S. adult population in 2014, and this percentage has remained fairly steady over the 66 years Gallup has been asking Americans about their religious identification.

Since 1948, 25% of Americans, on average, have been Catholic. The percentage was slightly higher than average in the late 1970s and early 1980s, and was slightly lower in the 2000s.

One remarkable aspect of this relatively stable trend is that during the same period, the percentage of Americans who have no formal religious identity has increased from roughly 1% to about 20% today. The rise in those with no religion has been accompanied by a decline in the percentages of Protestants and other non-Catholic Christians, the ranks of which have fallen from as high as 70% of the population, down to about 50% today. Catholics have been able to hold their own -- percentage-wise -- even as the unaffiliated percentage has risen significantly.

These results are based on Gallup's traditional "stand-alone" polls dating back to 1948. Religious identification is also measured as part of Gallup Daily tracking, and interviews with more than 170,000 individuals in 2014 showed a similar 23.9% of national adults interviewed identified as Catholic.

Almost a Third of U.S. Catholics Are Hispanic

One of the explanations for the stable representation of Catholics in the adult population over time is the increasing percentage of Hispanics in the U.S. population, coupled with the fact that the majority of Hispanics identify as Catholic. In Gallup's 2014 tracking data, 32% of Catholics identified as Hispanic, more than double the representation of Hispanics in the U.S. adult population. Sixty-one percent of Catholics are white, while 3% are black -- much lower than the black representation among Protestants.

Catholics No Longer Attend Church Services More Frequently Than Protestants

Catholics' church attendance no longer exceeds Protestants' church attendance. In May 2015, 44% of Catholics said they had attended church within the previous seven days, compared with 45% of Protestants.

Gallup's historical data show that Catholics' lower recent church attendance is dramatically different from that of the 1950s-1960s. Surveys from the 1950s, for example, showed that more than seven in 10 Catholics reported having attended church in the previous seven days, compared with figures in the 40% range for Protestants. Since then, church attendance among Protestants has remained stable, while it has dropped significantly among Catholics. Catholics lost their church attendance advantage over Protestants in the 1990s.

Catholics' Politics Match U.S. Average

While in Washington, Pope Francis will meet with Democratic President Barack Obama and will make a speech before a joint session of the Republican-controlled Congress. This bipartisanship fits nicely with the party identification of Catholics in the U.S., which is remarkably similar to what is found in the overall population. In 2014, 40% of both Catholics and non-Catholics identified as or leaned Republican, while 43% of both groups identified as or leaned Democratic.

This is a different situation from that of other religious groups, whose partisan identification tends to skew in one direction or the other. For example, 47% of Protestants and 71% of Mormons identify as or lean toward the Republican Party, well above the overall 40% of the population who are Republican. On the other hand, 61% of Jews identify with or lean toward the Democratic Party. All of this explains why Catholics have been a key swing group in recent presidential elections, much more so than other religious groups. The tendency for Catholics to mirror the overall population from a partisan perspective is a shift from the past, when Catholics tended to skew significantly more Democratic in their partisan and voting behavior.

Catholics Most Overrepresented in the East, Most Underrepresented in the South

Catholics are overrepresented compared with non-Catholics in the East, are underrepresented in the South and are distributed about equally compared with non-Catholics in the Midwest and West regions of the country.

The pope will be visiting the District of Columbia, New York and Pennsylvania during his trip to the U.S. New York state has the highest percentage of Catholics of these three geographic entities, at 36%, followed by Pennsylvania at 28% and then the District of Columbia, below average at 20%.

More broadly, Rhode Island's 45% Catholic is the highest percentage in the nation, while Mississippi's 8% is the lowest.

Americans' confidence in organized religion has dropped dramatically over the past four decades, hitting an all-time low this year of 42%. While Protestants' confidence in the church is also at a new low, Catholics' has stabilized.